Method and apparatus for chilling, storing and shipping edible material



Dec. 25,1962 w L. MORRISON 3,069,865

METHOD AND APPARATUS FOR CHILLING, STORING AND SHIPPING EDIBLE MATERIAL Filed Aug. 5, 1960 INVEN TOR.

Arrmzvzm Unite 3,069,865 METHQD AND APPARATUS FUR CHELLING,

all AND SHIPPING EDIBLE MATE- Willard L. Morrison, Lake Forest, Ill., assignor to Liquefreeze Company, line, New York, N.Y., a corporation of New York Filed Aug. 5, 1%60, Ser. No. 47,808 7 Claims. (Cl. 62-64) My invention relates to improvements in method and apparatus for chilling, storing and shipping edible material. This application is a continuation in part of my co-pending application Serial No. 586,205, filed May 21, 1956, now Patent No. 2,959,034.

I propose to pack edible material, preferably frozen food in the usual cartons containing a multiplicity of small packages. The cartons will be packed in an insulated container. It may be a railroad refrigeration car or motor vehicle as the case may be. After the container is filled with the material, the doors will be closed and liquid nitrogen at atmospheric pressure and -320 degrees F. will be poured into the container until a sufficient amount of nitrogen has been evaporated by the heat of the container contents to chill the container contents to a desired point.

In an arrangement such as this a serious problem arises in connection with the inhibition of eddy currents inside the container, which eddy currents materially increase the rate of temperature rise. The difiiculty is that the interior dimensions of the various containers in use by railroads or trucking companies are different. The dimensions of the cartons shipped by various packers are different so it is frequently impossible to come out even. There will always be substantial clearance left above the load and frequency vertical clearances will be left.

The container will usually be equipped with a grid of foraminous distribution tubes at the top and the load will not ordinarily touch that grid. I propose therefore as the load is packed to build up in consonance with the packing of .the load a mattress or mattresses of absorbent material, for example, shredded paper. As the various tiers of cartons are completed, this paper will be stuifed into the remaining clearances to form a liquid absorbent, liquid distributive, insulating mattress. This build up of the mattress or mattresses will continue as the car is being loaded and when it is loaded the mattress will be completed. Thus the size and shape of the mattress or mattresses are defined by the relationship between the load and the container.

Then when the container is closed and liquid nitrogen is discharged into the container, it first saturates the mattress spreading by capillary attraction therethrough. Having saturated the mattress and been distributed by it, the liquid pours down onto the load and chills it to the desired point.

Because the specific heat of the container contents is easy to determine; because the weight of the contents is known; because the time of shipment and storage is known; because the ambient outside conditions to be met can be predicted with reasonable accuracy and because the temperature of packing is known and because the object is to have the goods arrive at destination below a predetermined temperature, perhaps at zero degrees F., it is possible easily to figure out in advance the number of liters of liquid nitrogen at atmospheric pressure and 320 degrees F. which must be evaporated to lower the temperature to a point at which on arrival, the temperature will still be below the desired point.

As a result of the above, the predetermined amount of liquid nitrogen will be poured into the container. It may 3,069,855 Patented Dec. 25, 19fi2 be wasted but preferably the evaporated gas will be withdrawn in gaseous phase, reliquefied and returned to the container or saved for cooling subsequent contm'ners.

Once the predetermined amount of the liquid has been poured in the flow may be stopped, the container closed to prevent entrance of ambient air but left open enough to permit the escape of gas and it may start on its travels with the mattress saturated with the liquid. The liquid will flow down onto the goods during travel, continually cooling it until the liquid is all evaporated.

That ends the function of the mattress as an element in the distribution and storage of the liquid nitrogen but immediately thereafter, the mattress starts its important function of closing the clearances about the load and thus inhibiting eddy currents. Experience has taught that very substantial reduction in the rate of heat inflow results from the use of such a mattress. It is not a matter of building a mattress for use over and over again because conditions change with every loading. :A separate mattress must be assembled each time so it must be expendible and such a material as shredded paper is easily disposed of and is especially satisfactory material for the production of the mattress.

My invention is illustrated more or less diagrammatically in the accompanying drawings, wherein- FIGURE 1 is a longitudinal section through a refrigerator trailer with the door at the rear end;

FIGURE 2 is a section along the line 22 of FIG- URE 1.

Like parts are indicated by like numerals throughout the specification and drawings.

The insulated car or tractor 1 is open at one end or at the side as the case may be, closed by an access door 2. Material to be shipped may be packed in cartons 3 as closely as possible in the body. There will usually remain clearance at the top and quite often one side because the packages do not come out even in size with respect to the dimensions of the interior of the vehicle body.

A liquid supply 4 extends across the top of the body with each outside end removably capped as at 5. Distribution pipes 6 extend longitudinally of the body being fed by the supply pipe 4. Extending laterally from the distribution pipes are foraminous liquid discharge pipes 7 all just below the top of the vehicle and inside the insulation. Extending upwardly from the top of the vehicle body are a plurality of gas vent pipes 8 which may be removably capped at 9.

Frozen food, preferably in cartons, is brought in through the open door to fill the vehicle body. As packing of the container continues, I propose to fill the clearances above and on the side of the load by packing in an absorptive blanket of disposable material such as shredded paper which will fill the clearances above the load and between the load and the walls and door. This absorptive blanket will be built up as loading continues until when the vehicle is completely loaded, fills most if not all the clearances between the load and the walls and roof, and is shown at 10.

When the doors are closed, liquid nitrogen will be found saturating the blanket. When the blanket is saturated, the liquid nitrogen will flow down onto and about the food. This liquid nitrogen at atmospheric pressure and -320 degrees P. will be boiled by the relatively hot frozen food and the resultant gas will pass out through the uncapped vent pipes 8. These vent pipes may be allowed to waste nitrogen to atmosphere. Preferably, however, the uncapped vent pipes will be connected by ducts which are conventional and not illustrated to a reliquefaction plant which will reliquefy the gaseous nitrogen and return it through ducts not illustrated, connected 3 to the liquid supply pipe 4 a a coolant to cool the contents of the vehicle body.

When the necessary amount of liquid nitrogen has been poured in, the supply will be discontinued and the vehicle may go on its way without waiting for complete evaporation of all of the liquid nitrogen.

Preferably frozen food will be loaded, though it is possible, if desired, to pack unfrozen food and freeze it down to the desired low temperature.

The absorptive blanket accomplishes three purposes. It effectively distributes the liquid nitrogen over the load during the supply of liquid nitrogen to the vehicle. It retains for a short time excess liquid nitrogen so that it is possible to pour the nitrogen in more rapidly than it is evaporated, thus saving time of nitrogen supply and after the nitrogen has evaporated, it prevents convection currents and adds to the insulation and it makes it possible to compensate for lack of a full load.

If for some reason there is not enough material to completely fill the container, clearance spaces will result and thi will promote convection currents and warming of the load. Such wide open spaces when filled with the blanket of shredded paper or other suitable material are much less likely to result in dangerous heating.

I claim:

1. In combination, an insulated shipper container having a loading aperture and removable closure therefor, a plurality of packages of perishable material contained Within and generally filling said container, there being substantial clearances between the walls of the container and the packages, a mattress of loose, shredded paper packed into and filling said clearances, said mattress consisting of a continuous formation of adjoining shreds of paper which are held in place exclusively by contact with the Walls and the packages, means for saturating the mattress with liquid nitrogen at atmospheric pressure and 320 degrees F. including a discharge duct between the mattress and the wall of the zone.

2. In combination, an insulated shipper container having a loading aperture and removable closure therefor, a plurality of packages of perishable material contained within and generally filling said container, there being substantial clearances between the Walls of the container and the packages, a mattress of loose, shredded paper packed into and filling said clearances, said mattress consisting of a continuous formation of adjoining shreds of paper which are held in place exclusively by contact with the walls and the packages, means for saturating the mattress with liquid nitrogen at atmospheric pressure and 320 degrees F. including a discharge duct between the mattress and the wall of the zone, means for discharging gas from the container through the mattress in counter-current direction with respect to the iiow of liquid through the mattress toward the packages.

3. in combination, an insulated shipper container having a loading aperture and removable closure therefor, a plurality of packages of perishable material contained Within and generally filling said container, there being substantial clearances between the Walls of the container and the packages, a mattress of loose, shredded paper packed into and filling said clearances, said mattress consisting of a continuous formation of adjoining shreds of paper which are held in place exclusively by contact With the Walls and the packages, means for saturating the mattress with liquid nitrogen at atmospheric pressure and -320 degrees F. whereby liquid nitrogen passes downwardly therethrough, drops therefrom into contact with the packages, and means for discharging gas resulting from the contact of the liquid nitrogen with the packages through the mattress from the container.

4. The method of packing perishable material in an insulating container which consists in loading therein a plurality of packages of perishable material to substantially fill it and as the packages are being loaded, building up in substantially all clearances between the packages and. the walls of the container a body of loose, permeable, liquid absorptive material which fills the clearances between, said body comprising a continuous formation of adjoining pieces of said material and being held in position solely by contact with the packages and the Walls, and introducing a predetermined amount of liquid nitrogen into the packed insulated container.

5. The method of freezing perishable material which consists in loading a plurality of packages of the material in an insulating container to substantially fill it and as the packages are being loaded building up in substantially all the clearances between the packages and the Walls of the container a body of loose, permeable liquid absorptive material which fills the clearances between, said body comprising a continuous formation of adjoining pieces of said material and being held in position solely by contact with the packages and the walls, and after the container is loaded pouring into it liquid nitrogen at atmospheric pressure to saturate the absorptive body and Wet the packages as the liquid drips out of the body onto the packages.

6. The method of freezing perishable material which consists in loading a plurality of packages of the material in an insulating container to substantially fill it and as the packages are being loaded, building up in substantially all the clearances between the outermost packages and the walls of the container a body of loose, permeable, liquid absorptive material which fills the clearances between, said body comprising a continuous formation of adjoining pieces of said material and being held in position solely by contact with the packages and the walls, and after the container is loaded pouring into it liquid nitrogen at atmospheric pressure to saturate the absorptive body and Wet the packages as the liquid drips out of the body Onto the packages, discontinuing the supply of liquid nitrogen before the liquid in the permeable body has been evaporated and closing the container for shipment and storage.

7. The method of freezing perishable material which consists in packing a multiplicity of separate packages of the material in an insulated storage and shipment zone with clearances between the assembly of packages and the boundaries of the zone, building up as such packing continues a mattress of disposable, permeable, liquid absorptive material to fill substantially all the clearances, said mattress comprising a continuous formation of adjoinin pieces of said material, then closing the zone and supplying liquid nitrogen at atmospheric pressure to the zone above the mattress to saturate it and cause the liquid to drip therefrom into contact with the packages, then While the mattress is still saturated, ceasing the supply of liquid and closing the zone for shipment and storage.

References Cited in the file of this patent UNITED STATES PATENTS 2,568,975 Warne Sept. 25, 1951 2,618,939 Morrison Nov. 25, 1952 2,890,123 Brown et al. June 9, 19 59 

